Re: [Qemu-devel] [PATCH 0/5] QEMU VFIO live migration

[Gonglei (Arei)]

> -----Original Message-----
> From: Zhao Yan [mailto:address@hidden
> Sent: Thursday, February 21, 2019 12:08 PM
> To: Gonglei (Arei) <address@hidden>
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> Subject: Re: [PATCH 0/5] QEMU VFIO live migration
> 
> On Thu, Feb 21, 2019 at 03:33:24AM +0000, Gonglei (Arei) wrote:
> >
> > > -----Original Message-----
> > > From: Zhao Yan [mailto:address@hidden
> > > Sent: Thursday, February 21, 2019 9:59 AM
> > > To: Gonglei (Arei) <address@hidden>
> > > Cc: address@hidden; address@hidden;
> > > address@hidden; address@hidden;
> > > address@hidden; address@hidden; address@hidden;
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> address@hidden;
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> > > address@hidden; address@hidden;
> address@hidden;
> > > address@hidden; address@hidden; address@hidden;
> > > address@hidden
> > > Subject: Re: [PATCH 0/5] QEMU VFIO live migration
> > >
> > > On Thu, Feb 21, 2019 at 01:35:43AM +0000, Gonglei (Arei) wrote:
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Zhao Yan [mailto:address@hidden
> > > > > Sent: Thursday, February 21, 2019 8:25 AM
> > > > > To: Gonglei (Arei) <address@hidden>
> > > > > Cc: address@hidden; address@hidden;
> > > > > address@hidden; address@hidden;
> > > > > address@hidden; address@hidden; address@hidden;
> > > > > address@hidden; address@hidden;
> > > address@hidden;
> > > > > address@hidden; address@hidden; address@hidden;
> > > > > address@hidden; address@hidden; address@hidden;
> > > > > address@hidden; address@hidden;
> > > address@hidden;
> > > > > address@hidden; address@hidden; address@hidden;
> > > > > address@hidden
> > > > > Subject: Re: [PATCH 0/5] QEMU VFIO live migration
> > > > >
> > > > > On Wed, Feb 20, 2019 at 11:56:01AM +0000, Gonglei (Arei) wrote:
> > > > > > Hi yan,
> > > > > >
> > > > > > Thanks for your work.
> > > > > >
> > > > > > I have some suggestions or questions:
> > > > > >
> > > > > > 1) Would you add msix mode support,? if not, pls add a check in
> > > > > vfio_pci_save_config(), likes Nvidia's solution.
> > > > > ok.
> > > > >
> > > > > > 2) We should start vfio devices before vcpu resumes, so we can't 
> > > > > > rely
> on
> > > vm
> > > > > start change handler completely.
> > > > > vfio devices is by default set to running state.
> > > > > In the target machine, its state transition flow is
> running->stop->running.
> > > >
> > > > That's confusing. We should start vfio devices after vfio_load_state,
> > > otherwise
> > > > how can you keep the devices' information are the same between source
> side
> > > > and destination side?
> > > >
> > > so, your meaning is to set device state to running in the first call to
> > > vfio_load_state?
> > >
> > No, it should start devices after vfio_load_state and before vcpu resuming.
> >
> 
> What about set device state to running in load_cleanup handler ?
> 

The timing is fine, but you should also think about if should set device state 
to running in failure branches when calling load_cleanup handler.

Regards,
-Gonglei